Farther and further have been used interchangeably by many writers since the Middle English period. According to a rule of relatively recent origin, however, farther should be reserved for physical distance and further for advancement along a nonphysical dimension. Thus 74 percent of the Usage Panel prefers farther in the sentence If you are planning to drive any farther than Ukiah, you'd better carry chains; whereas 64 percent prefers further in the sentence We won't be able to answer these questions until we are further along in our research. In many cases, however, the distinction is not easy to draw. If we may speak metaphorically of a statement that is far from the truth, for example, the analogous use of farther should be allowed in a sentence such as Nothing could be farther from the truth, though Nothing could be further from the truth is also justifiable.

Farther and further have been used interchangeably by many writers since the Middle English period. According to a rule of relatively recent origin, however, farther should be reserved for physical distance and further for advancement along a nonphysical dimension. Thus 74 percent of the Usage Panel prefers farther in the sentence If you are planning to drive any farther than Ukiah, you'd better carry chains; whereas 64 percent prefers further in the sentence We won't be able to answer these questions until we are further along in our research. In many cases, however, the distinction is not easy to draw. If we may speak metaphorically of a statement that is far from the truth, for example, the analogous use of farther should be allowed in a sentence such as Nothing could be farther from the truth, though Nothing could be further from the truth is also justifiable.